Paleontology: Ancient Marine Reptiles is a four-lesson course teaching a comprehensive overview of the evolutionary changes that occur when air-breathing terrestrial animals return to water. This course examines the diversity, adaptations, convergence, and phylogenetic relationships of extinct marine reptiles. Students will explore three major groups of marine reptiles: ichthyosaurs, plesiosaurs, and mosasaurs. Watch a preview of the course here: https://uofa.ualberta.ca/courses/paleontology-marine-reptiles

From the lesson

Mosasauroids

Welcome to the final lesson in Palaeontology: Ancient Marine Reptiles. The lesson you just finished gave you an in depth look at one of the most morphologically disparate groups of marine tetrapods to ever live. There were the turtle-shaped placodonts with crushing teeth; the extraordinarily long-neck elasmosaurs; and the pliosaurs with jaws massive enough to take on nearly any prey. Even though sauropterygians evolved many different body plans, they all shared certain adaptations for solving the aquatic problem such as live birth and appendicular locomotion.
In contrast, the final group we will investigate showed convergence on one morphotype. The mosasaurs, though diverse, were all fairly long reptiles, with large jaws, four flippers and a long, lobed tail. You may recognise one of them from Jurassic World, where an enormous genetically-engineered Mosasaurus leaped out of the water to eat a shark.
This last lesson will once again start by examining the diversity of the group, from their terrestrial origins to last days of the Cretaceous when they ruled as apex predators. We will investigate the specific adaptations of the group to the aquatic problem, and finish with an overview of the history of mosasaurs throughout time and space.
Please enjoy the last lesson of Palaeontology: Ancient Marine Reptiles. It is an appropriate way to finish this course since the mosasaurs were among the largest and most powerful marine predators to ever live, and were the last major marine reptile group to evolve during the Mesozoic.